Tutorial 26 : How to Fix OpenCart Blank Page

1. Add the following code to 'index.php' and/or 'admin/index.php'

// Error
ini_set(‘display_errors’,1);
ini_set(‘error_reporting’,’E_ALL’);

2. Enable error display

If you can access the admin folder, go to System > Settings > Edit Store > Server tab, and set Error Display to Yes.
If not, you can manually edit the value of the key "config_error_display" in the oc_setting table via phpMyAdmin.
Or, execute the following line of code :

$this->db->query(“UPDATE `”.DB_PREFIX.”setting` SET `value` = ‘1’ WHERE `”.DB_PREFIX.”setting`.`key` = ‘config_error_display'”);